Project Summary/Abstract: Genetic control of mitochondria is nearly completely lacking, however, the utility of such tools would be transformative to numerous fields of biomedical science. Developing genetic methods to knockdown or express/rescue endogenous mitochondrial genes would be a powerful research tool but would also immediately enable the development of novel therapies. We have developed novel vectors (mtTRES) that targeted RNAs to mitochondria and shown their ability to reduce the expression of endogenous genes in animals and human cells. We have also developed vectors capable of expressing long, coding RNAs to mitochondria allowing us to perform overexpression/rescue experiments. We propose to utilize mitochondrial-targeted riboendonucleases as an alternative method to reduce expression of endogenous genes but also to willfully process mtTRES expressed RNAs and facilitate their efficient expression. The development of novel methods to genetically manipulate mitochondrial gene expression in animals, which will be validated in human cells will have a broad impact on the fields of aging, mitochondrial biology and neurodegenerative disease research.